Differentiation of transparency in a lens cell involves a series of stages in which organelles disappear, membranes and metabolism become specialized and cytoplasmic proteins are concentrated into a homogeneous, transparent single phase. The results of the previous studies indicate that opacification may occur in stages that resemble the reversal of normal lens cell differentiation. The homogeneous cellular structure becomes disorganized and the cytoplasm is converted from a single transparent phase into two separate phases as light scattering increases. The transition from transparency to opacity is a continuous process which may include an early precataractous stage that is present prior to the observation of obvious light scattering in vivo. Based on the findings of the past project period, I propose the hypothesis that cataract formation includes an early stage in which abnormal molecular interactions initiate subtle structural lens cell opacification. The hypothesis will be tested through the following aims: Aim I: Characterization of the Early Stages of Opacification. Aim II: Quantification of Molecular Interactions in Lens Cytoplasm During Early Stages of Cataract Formation. Aim III: Characterization of Oscillations in Lens Growth During Development of Cataract. The results of these studies are expected to provide an animal model for the early stages of human cataract formation when the opportunity for non-surgical prevention of opacification is greatest.